San Hōjō, mother to Shūsaku Hōjō and mother-in-law to Suzu Urano after her marriage, resides with her husband Entarō Hōjō in Kure. Their home overlooks the naval harbor. A leg injury limits San's mobility and domestic capabilities, creating a practical need for Suzu's assistance in household duties, a factor Shūsaku denies motivated their marriage.

San possesses a gentle, compassionate, and kind-hearted nature. She defies the era's conventions for arranged marriage mothers-in-law, treating Suzu with respect and equality, cultivating warmth within the family. This kindness endures through wartime hardships like food rationing and air raids. Her husband Entarō works as an aircraft engine engineer at Hiro Naval Arsenal. During the March 1945 Kure bombing, Entarō goes missing but is later found injured at Kure Naval Hospital.

Amidst familial tensions, such as her widowed daughter Keiko Kuromura's initial coldness towards Suzu, San provides a calm, stable presence. She offers emotional continuity through tragedies, including the deaths of Suzu's Hiroshima family and the loss of her granddaughter Harumi. San remains a consistently nurturing figure across all narrative arcs, embodying domestic resilience without undergoing significant personal change.

The character appears in the original manga, the 2016 anime film, its 2019 extended version *In This Corner (and Other Corners) of the World*, and live-action adaptations, with consistent portrayal of her traits and circumstances. No pre-marriage background or independent activities outside the household are detailed.